X-ray computed tomography is an imaging method which is primarily used for medical diagnosis and for material analysis. In X-ray computed tomography an X-ray emitter and an X-ray detector that cooperates with the X-ray emitter rotate about an object to be examined. Images are taken at various angular positions of X-ray emitter and X-ray detector, wherein the object to be examined can be moved along the axis of rotation. The individual images are each a projection of the object to be examined. At the end of the series of images, which is also called a “scan”, the projections are processed in such a way that a three-dimensional, tomographic X-ray image is produced. Therefore carrying out a series of images will also be called a tomographic recording below. The quality of the resulting X-ray image is significantly influenced by the choice of scanning protocol. A scanning protocol includes values for parameters which determine the exact progress of the tomographic recording of an X-ray image.
A scanning protocol can also include values for parameters which influence the subsequent reconstruction of an X-ray image. The parameters can be by way of example intensity values of the X-ray radiation. Such intensity values can be modulated so as to be dependent on the projection angle in particular. The intensity values are specifically achieved by way of control of the X-ray emitter, i.e. by way of example by control of the current or voltage of an X-ray tube. The parameters of the scanning protocol can also include settings for filters or screens. In the medical environment the selection of a suitable scanning protocol is important in order to avoid unnecessary exposure of the patient to radiation as well as for the quality of the resulting image. If X-ray images of patients which absorb X-ray radiation to a particularly high or low degree are to be made, an existing scanning protocol must either be modified or a new scanning protocol which is suitable for such a case must be created. If more and more scanning protocols are created and retrievably stored, it becomes increasingly more laborious for the user of an X-ray tomograph to select a suitable scanning protocol from the large number of stored scanning protocols.
An operating method for an imaging device for improved selection of a contrast medium protocol is known from DE 10 2006 001 090 B4. A stored contrast medium protocol is selected from a database in which parameters of a contrast medium administration are stored. At least one linked scanning protocol relating to the selected contrast medium protocol is also identified in the database using a stored linkage parameter associated with the contrast medium protocol. The, or any, protocol identified in this way is then output as the scanning protocol associated with the selected contrast medium protocol.